Abstract
High power laser facilities push the frontier of materials science by rapidly generating immense pressures through pulsed laser shock compression and release. Such extreme stresses and strain-rates reveal unique deformation mechanisms and phases that drive processes ranging from planetary formation to inertially confined fusion. Yet, our experiments persist for only nanoseconds and are exceedingly challenging to monitor. Results are often inferred from before and after microscopy or rely entirely on indirect measures of stress and strain. Massive computer simulations enable us to bridge this knowledge gap by evaluating extreme environments with atomic resolution. The precise simulation of material defects informs our interpretation of experimental results, provides a unique means to evaluate material strength, and holds the potential to directly visualize mechanisms governing the properties of materials. Here we specifically evaluate the shock compression of tantalum utilizing high performance computing simulations of up to one billion atoms. We identify unexpected phase transformations and probe the ultimate tensile strength of the material.